Java methods

Methods represent the business logic of the application and it defined inside the class.
Ex: I have a java class, in that class, I want to do add two numbers so we should keep this logic of addition in methods.

  • The method should have a signature and signature represents method name and parameters.
  • A java class contains multiple methods.
syntax
<access modifier> <return type> <method_Name>(parameters){
//method body
//business code
}
Access modifiers for  methods:
Access modifiers applicable to methods are public, private to check the visibility of methods to other classes.
Return type:
The return type is the data type of the value returned by the method, if the method doesn't return value, return type value should be void.
Method_Name:
The method name is any legal identifier.
Parameters:
Parameters should placed in parenthesis() by keeping(;).if there is no parameters ,we must use use empty parameters.
Naming a method
Method name is any legal identifier. method name should be the verb in lower case.if there is multi-word method name that begins with lowercase and first letter of each second word must capital letter.
How to invoke methods?
In java we have two types of methods 
  • Instance methods
  • Static methods
Instance methods:
Instance methods are  invoked by using Object reference  a class.
package com.practice;
public class Instance_Method_Demo {
 int x = 30;// instance variable declaration
 int y = 30;// instance variable declaration
 // instance method
 public void add() {
  System.out.println("sum of numbers:" + (x + y));

 }
 public static void main(String[] args) {
  // Object creation
  Instance_Method_Demo instance_Method_Demo = new Instance_Method_Demo();
  instance_Method_Demo.add();// invoking instance method with object
         // reference }

}
output
sum of numbers:60
Static methods:
Static methods are invoked by using class name like below
<classname>.<static_method>
Example
package com.practice;
public class Static_Method_Demo {
 static int x = 30;// static variable declaration
 static int y = 30;// static variable declaration
 // static method
 public static void add() {
  System.out.println("sum of numbers:" + (x + y));

 }

 public static void main(String[] args) {
  // invoking static method by using class name  Static_Method_Demo.add();
 }

}
output
sum of numbers:60
Example  for method with parameters
package com.practice;

public class Static_Method_Demo {
 static int x;// static variable declaration
 static int y;// static variable declaration
 // static method
 public static void add(int x,int y) {
  System.out.println("sum of numbers:" + (x + y));

 }

 public static void main(String[] args) {
  // invoking static method by using class name  Static_Method_Demo.add(30,30);
 }

}
output
sum of numbers:60